1. Field of the Invention
The present invention relates to an apparatus and method for producing reproduction time of an optical disc, and, more particularly, to an apparatus and method for producing the reproduction time by detecting time codes from system data of the optical disc.
2. Description of Prior Art
A Compact Disc (referred to as xe2x80x9cCDxe2x80x9d hereinafter) is currently one of the most widely used recording media for optical discs. The CD is broadly used as a recording medium in various recording media fields, including the audio and computer fields. Some of the advantages achieved by using the CD as a recording medium are that the CD has a greater recording capacity than other conventional recording media, the CD can be preserved permanently, and the CD is easy to move due to its small size. Additionally, CDs record data digitally, preserving the data without deterioration even if the CD is used repeatedly.
A Digital Video Disc (referred to as xe2x80x9cDVDxe2x80x9d hereinafter) has been recently developed as a new recording medium. The DVD has all the above-noted characteristics of the CD. Additionally, the DVD is able to store moving images as well as numbers, characters, figures and voices. The recording capacity of one recording side of a DVD is about 6-7 times the recording capacity of the CD. Consequently, the DVD has become popular as an alternative recording medium to the CD. Furthermore, the DVD has become the focus in the recording media market, including the video, audio and computer fields.
The CD and DVD, as illustrated in FIG. 1, generally are composed of a Lead-In area, a data recording area and a Lead--Out area. The Lead-In area is placed in a predetermined area near the center of the disc, the Lead-Out area is placed at the periphery of the disc, and the data recording area is placed therebetween, extending from the end of the Lead-In area toward the periphery of the disc before the Lead-Out area begins. The disc has a plurality of tracks for storing data. Main data, e.g. video/audio data, are stored in each track as a sector/unit. That is, predetermined video/audio data are stored on the plurality of tracks on the recording surface of the optical disc, as a sector/unit. Data stored in the CD and/or DVD is reproduced by reproducing the data stored in the sectors/units.
The length of a sector on a track in a CD is preset. In each track, there exists an absolute address which announces positions on the track based on the sectors. Since the CD is frequently used in audio and computer related applications, and data used in the fields is arranged such that data of the same volume occupies the same amount of space, each sector of a formatted CD having a pre-set length enabling those sectors to store data having a fixed volume. When the absolute address is detected for a sector on a track whose data is being reproduced, the position of the data being reproduced on the track, and therefore the related reproduction time, may be produced. That is, reproduction time is determined based on the relative positions of recorded data since CDs store constant length sections of data.
By contrast, data stored in the DVD represents moving images, such as video signals. The data representing the moving images is stored such that the storage space occupied by a predetermined amount of data is variable and dependant on the position of the data being reproduced from the DVD. Therefore, the reproduction time of a certain amount of data stored on the disk is not fixed, nor is the reproduction time dependant on the position (e.g., absolute address) of the data on the DVD. Further, when recording on a DVD, moving images such as video signals are recorded as sectors/units, with the length of each sector differing according to the volume of the data or the recording position. As a result, if only the address of a sector is detected, it is not possible to determine the physical reproducing position and the reproduction time of the data on the DVD which is presently reproduced.
An object of the present invention is to improve upon the conventional reproduction of data stored in the DVD.
To accomplish this and other objects, a first embodiment of the present invention includes an apparatus and method for determining reproduction time of a program on a disk. A first device determines time code data based on control data that indicates a position of the program on the disk and that is stored on the disk. A second device determines reproduction time of the program based on the time code data.
The first device may include a detector for detecting the control data stored on the disk, and a processor for determining the time code data based on the control data. The processor computes the time code data based on the control data. More specifically, the processor generates an output based on first time code data associated with first data units and second time code data associated with second data units, each first time code data indicating reproduction time of an associated first data unit and each second time code data indicating reproduction time of an associated second data unit. The second device determines the reproduction time based on the output generated by the processor.
Alternatively, the processor may generate an output based on first time code data associated with first data units and second time code data associated with a second data unit, where each first time code data indicates reproduction time of an associated first data unit and the second time code data corresponding to reproduction time of at least the associated second data unit, and where the second device determines the reproduction time based on the output generated by the processor. In this alternative case, the second time code data corresponds to a summation of reproduction time for the associated second data unit and other second data units preceding the associated second data unit.
A second embodiment of the present invention also includes an apparatus and method for determining reproduction time of a program on a disk. This embodiment includes a detector for detecting first time code data associated with first data units, a detector for detecting second time code data associated with second data units, and a device for determining a reproduction time based on the detected first and second time code data.
Each first time code data is included in a header of an associated data unit. Each first time code data indicates reproduction time of an associated first data unit, each second time code data indicates reproduction time of an associated second data unit.
A detector may also be provided for detecting additional time code data associated with a data unit in a header of a DVD corresponding to a video object unit (VOBU). The additional time code data corresponds to reproduction time of the associated second data unit, and to a summation of reproduction time for said associated second data unit and other second data units preceding said associated second data unit. In this case, the processor calculates the reproduction time based on the first time code data and the additional time code data.
The reproduction time may represent an amount of time included in a portion of a program already reproduced, or it may represent an amount of time in a portion of a program remaining to be reproduced.
If the later case, a detector may be used for detecting a total reproduction time of a program being reproduced, and a processor is used for calculating said reproduction time based on a difference between said total reproduction time and the above-described time code data. For instance, when the second or additional time code data is detected, the processor may calculate the reproduction time based on a difference between the total reproduction time and various combinations of the first time code data, the second time code data, and the additional time code data.
The reproduction time (the performed time and/or the remaining time) of the optical disc is able to be displayed on the screen of a display according to the present invention in response to the request of a user. Therefore, the present invention has the advantage that the user maybe able to acquire the performed time and/or the remaining time of the present title.
In each of the above-described cases, the first and second data units are stored on a digital versatile disk (DVD), the first data units corresponding to program chains (PGCs) and the second data units corresponding to cells.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of example only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.